ericj
Headphoneus Supremus
- Joined
- Aug 2, 2005
- Posts
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Somewhere between homebrewheadphones.com and some of the AKG style and Grado style parts on thingiverse i got thinking about making an entire headphone chassis at home from a minimum of different kinds of parts.
Largely 3d printed. Modular. Lending itself to endless tinkering, so a minimum of glued or easily worn out parts where it matters.
For a while i was thinking about a chassis inspired by Grado and a little bit by Stax.
In the old SR-80 and i suppose a lot of grados that i don't have first hand experience with, the driver gets glued into a tube section that gets glued into a larger tube section and the yoke connects to the larger tube section with some pins that fit into a hole in the yoke and a hole in the tube and have a little integral spacer. It's likely that the total length of the resulting assembly and the flare at the back are a bit like a bass port on a reflex speaker.
The Stax SR-30 works a lot the same way. It's an outer cup and an inner cup. The outer cup includes the baffle to which the driver is adhered. The inner cup has a grille and retains any and all damping materials. The difference is that the only thing that holds the inner and outer cups together is the pins that connect to the yoke.
So i think if i were designing 3d-printable Grado-style headphone cups, I would go with the SR-30 style assembly where the pins hold it together.
I have a little bit of experience with both fused deposition (filament through a hot nozzle) 3d printing and liquid resin 3d printing. Long skinny objects that have really smooth surfaces and don't snap easily are not really something 3d printers are great at. If you're making thousands of something, you have injection molding to lean on, as well as companies that will crank out steel rods with chrome plating and knurled ends.
If you're making ONE of something, carbon fiber rods and tubes aren't expensive on aliexpress and probably glue really well to 3d printable plastics with the right adhesives. You can cut them easily with a dremel. So in a Grado style chassis, cheap carbon fiber rods can provide the pin that connects the yoke to the cup and the pin that connects the yoke to the headband. https://www.aliexpress.com/item/32573564619.html
A 3d printed yoke has to be a bit beefier than one that is injection molded, but that is not a big deal.
The arch of the SR-80 style chassis is a metal band with a cover that is largely cosmetic, and the blocks that connect that to the pins that come off the yoke. The blocks are super easy to print. The metal band is a piece of cake if you have a few hundred bucks worth of sheet metal working equipment, or maybe you can get stainless steel hair bands on aliexpress and perhaps all you have to do is design the block to clamp onto them, or maybe cut them to length and drill a hole in each end. Like these. https://www.aliexpress.com/item/32913953633.html
3d printed headband arches exist but you pretty much have to print them in ABS for long-term durability. Or maybe HIPS or nylon or some other more demanding material. PLA will work great for a while and either break all at once or flow over time until you have no clamping force. PETG is too floppy in my experience, and you can't glue stuff to it easily.
And that's where i come to the K240 style chassis. Or maybe more specifically K270 style. Grado style might be ideal for supra-aural but perhaps isn't ideal for circum-aural.
Maybe after knocking up some jigs, the K240 style wire headband is super easy to make out of the copper-plated TIG welding rods specified for mild steel that are crazy cheap and available in a multitude of diameters anywhere metal exists. I mean you bend it into a ring, take two rings and put a couple more bends into them. Cover it with tubing of . . . . some kind.
AKG injection molds the plastic blocks that connect the outer headband to the cups. I've bought a lot of old and broken headphones in the K240/141/270 family and sometimes one of the wires breaks out of the block. Usually some well-mixed, high quality epoxy provides a durable fix, and i don't see why i couldn't 3d print a block that just has a channel for the wire on each side and a jig to hold the parts until the epoxy has cured.
The K240 style cardan joint is admirable but puts some limitations on the diameter and depth of the driver assembly. It's great if you have a small to medium diameter driver. But i like orthos and electrostatics too and they are often large diameter and picky about what is directly behind them.
The K270 chassis affords a much larger cup volume. It just has a vertical pivot, and relies on the flex of the headband for the horizontal tilt, though it wouldn't be difficult to build in a few degrees of toe for better head fit.
Largely 3d printed. Modular. Lending itself to endless tinkering, so a minimum of glued or easily worn out parts where it matters.
For a while i was thinking about a chassis inspired by Grado and a little bit by Stax.
In the old SR-80 and i suppose a lot of grados that i don't have first hand experience with, the driver gets glued into a tube section that gets glued into a larger tube section and the yoke connects to the larger tube section with some pins that fit into a hole in the yoke and a hole in the tube and have a little integral spacer. It's likely that the total length of the resulting assembly and the flare at the back are a bit like a bass port on a reflex speaker.
The Stax SR-30 works a lot the same way. It's an outer cup and an inner cup. The outer cup includes the baffle to which the driver is adhered. The inner cup has a grille and retains any and all damping materials. The difference is that the only thing that holds the inner and outer cups together is the pins that connect to the yoke.
So i think if i were designing 3d-printable Grado-style headphone cups, I would go with the SR-30 style assembly where the pins hold it together.
I have a little bit of experience with both fused deposition (filament through a hot nozzle) 3d printing and liquid resin 3d printing. Long skinny objects that have really smooth surfaces and don't snap easily are not really something 3d printers are great at. If you're making thousands of something, you have injection molding to lean on, as well as companies that will crank out steel rods with chrome plating and knurled ends.
If you're making ONE of something, carbon fiber rods and tubes aren't expensive on aliexpress and probably glue really well to 3d printable plastics with the right adhesives. You can cut them easily with a dremel. So in a Grado style chassis, cheap carbon fiber rods can provide the pin that connects the yoke to the cup and the pin that connects the yoke to the headband. https://www.aliexpress.com/item/32573564619.html
A 3d printed yoke has to be a bit beefier than one that is injection molded, but that is not a big deal.
The arch of the SR-80 style chassis is a metal band with a cover that is largely cosmetic, and the blocks that connect that to the pins that come off the yoke. The blocks are super easy to print. The metal band is a piece of cake if you have a few hundred bucks worth of sheet metal working equipment, or maybe you can get stainless steel hair bands on aliexpress and perhaps all you have to do is design the block to clamp onto them, or maybe cut them to length and drill a hole in each end. Like these. https://www.aliexpress.com/item/32913953633.html
3d printed headband arches exist but you pretty much have to print them in ABS for long-term durability. Or maybe HIPS or nylon or some other more demanding material. PLA will work great for a while and either break all at once or flow over time until you have no clamping force. PETG is too floppy in my experience, and you can't glue stuff to it easily.
And that's where i come to the K240 style chassis. Or maybe more specifically K270 style. Grado style might be ideal for supra-aural but perhaps isn't ideal for circum-aural.
Maybe after knocking up some jigs, the K240 style wire headband is super easy to make out of the copper-plated TIG welding rods specified for mild steel that are crazy cheap and available in a multitude of diameters anywhere metal exists. I mean you bend it into a ring, take two rings and put a couple more bends into them. Cover it with tubing of . . . . some kind.
AKG injection molds the plastic blocks that connect the outer headband to the cups. I've bought a lot of old and broken headphones in the K240/141/270 family and sometimes one of the wires breaks out of the block. Usually some well-mixed, high quality epoxy provides a durable fix, and i don't see why i couldn't 3d print a block that just has a channel for the wire on each side and a jig to hold the parts until the epoxy has cured.
The K240 style cardan joint is admirable but puts some limitations on the diameter and depth of the driver assembly. It's great if you have a small to medium diameter driver. But i like orthos and electrostatics too and they are often large diameter and picky about what is directly behind them.
The K270 chassis affords a much larger cup volume. It just has a vertical pivot, and relies on the flex of the headband for the horizontal tilt, though it wouldn't be difficult to build in a few degrees of toe for better head fit.